Family

Taxus baccata, yew

Taxaceae

Meaning of the Name

Taxus
Possibly from the Greek ‘taxon’, ‘bow’ as a result of the use of its
wood to make bows. Persian has ‘tachš’ for ‘bow’. A mummy from the
Chalcolithic age, around 4000BC, was found with an unfinished bow
made of yew so its use for this purpose goes back much further than
the English long bowmen usually associated with it.

baccata
From Latin ‘bacca’, ‘berry’

Common Names and Synonyms

yew, Irish yew, English yew

How Poisonous, How Harmful?

Taxus baccata, yew

All parts, except the flesh of the berries, contain taxin(e) a
complex of alkaloids which is rapidly absorbed. Also present are
ephedrine, a cyanogenic glycoside (taxiphyllin) and a volatile oil.

Where poisoning does occur, in animals or humans, there may be no
symptoms and death may follow within a few hours of ingestion. If
symptoms do occur, they include trembling, staggering, coldness,
weak pulse and collapse.

Yew is one of the plants where the poison is not destroyed when
the plant dies. Thus, branches removed from a yew by high winds or
pruning will retain their poison.

Though the berries are harmless, the seed within is highly toxic.
Unbroken it will pass through the body without being digested but if
the seed is chewed poisoning can occur with as few as three berries.

Taxus baccata, yew

Incidents

Most incidents with yew relate to animals though it was eaten, in
the 1980s, by four prisoners as a means of suicide. Three of
the four succeeded.

The interactive CD-ROM produced by St Thomas' and Kew Gardens
cites a number of case reports all involving ingestion of leaves or
bark. In one case it is noted that a nineteen month old child
accidentally ingested some plant material. Intact seeds were found
in his stools confirming that these are not digested. The child
recovered.

Farmers have reported cases of poisoning in cattle when dead yew
clippings have been dumped on grazing land. The assumption is
that someone clipped a yew hedge in the garden, left the clippings
to wither thinking that would render them safe before 'recycling'
them by dumping them on farmland.

A visitor to the Alnwick Garden Poison Garden talked about his
elderly neighbour who, being no longer able to manage it himself,
had a group of young people in to tidy up his garden. They trimmed
his yews and threw the clippings over the fence into the field at
the bottom of the garden where three heifers died after eating the
cuttings.

Folklore and Facts

Some years ago, it was found that the taxol found in yew
could be used to produce chemotherapy treatments for breast
and other cancers. The drug produced in this way is called paclitaxel.
(Until someone was kind enough to correct me, I was
one of the many people who thought tamoxifen was produced from
yew. It is not. Tamoxifen is a synthetic drug.) For some time, large
gardens made a point of keeping their yew prunings and passing
these to companies to extract the taxol and produce these drugs.
This was an expensive process and produced only limited amounts
of the drug. Since then, however, it has been discovered that
taxol is produced from a fungus that lives in the yew. Other
fungi have also been found that are able to be used to produce
paclitaxel. With some, artificially brewing is possible and, once that process is
scaled up, it should reduce the cost and
increase the availability of breast cancer treatments.

Though toxic to most animals, deer do graze on yew and gardeners
are advised to avoid growing yew if there is a possibility of deer
getting into the garden because it is a favourite food. That said,
the list of plants which deer will browse is a very long one and
there are reports of poisoning incidents so it may be large amounts
are toxic to deer.

The idea that yew was grown in churchyards for making longbows is
a myth. Bows were made, primarily, from the trunk of the tree so the tree
was
destroyed. In addition, yew grown in Britain is too brittle so the
famous English longbow was made from wood imported from Europe.

The roots of the yew are very fine and will grow through the eyes
of the dead to prevent them seeing their way back to the world of
the living.

Sources - Galen

Galen was a Greek who worked as a doctor in Rome. He lived
from about 130AD to about 215AD. He spent much time dissecting
animals to try and understand the workings of the body and was the
first to conclude that the kidneys are where urine is formed rather
than the bladder. He also discovered the heart valves and found that
the arteries carry blood around the body and not air as was thought.
Many of his other discoveries were, however, erroneous and he fell
out of favour during the Renaissance.

That we know so much of Galen’s writings is due to their translation
into Arabic, during the 9th century, by Hunayn ibn Ishaq. Many of
the English herbals refer to Galen to support their descriptions of
the efficacy of plant remedies.

Yew is very long-lived and, in many cases, the yew tree in the
churchyard predates the church so, the church was built round a yew
tree because the pagan belief about the roots was so deep-seated.

Its longevity leads to its featuring in tales of reincarnation.
If two yews are intertwined it is believed that they grew after yew
stakes were driven into the chests of lovers whose relationship
appalled their community.

Many place names have their origins in particular trees. York is
a corruption of an Anglo-Saxon word meaning ‘the place where yew
grows’.

John Gerard quotes Galen and others as saying that the yew is
very venomous taken internally and that sleeping under a Yew can
cause sickness and oftentimes death. He then dismisses these
stories by saying that ‘when I was young and went to school, divers
of my school fellows and likewise myself did eat our fills of the
berries of this tree and hath not only slept under the shadow
thereof, but among the branches also, without hurt at all, and that
not one time, but many times’.

Thomas Johnson resolves the difference of opinion between the
foreign ancient sources and
Gerard by asserting that the yew in
England is not poisonous but, in other countries, it is highly
venomous.